The difference is that a revovolver has flash comming from the cylinder gap while the c models have it comming from the top of your weapon along the same plane as your sights. Under low light this could potentially deminish your night vision and lead to a problem aquiring a proper sights picture after the first round. I don't want to carry a c model for that reason and one other which is I don't see the point esspecially with a 9mm it just seems pointless but if it works for you then go for it.